[An improved method for the combination of modified insulin chains (author's transl)]

A procedure is described in which the yields of the combination of insulin A and B chains, especially of modified chains, are increased. The chains are reduced simultaneously in 8M urea buffer at pH 8.6 with 2-mercaptoethanol. The thiol chains are not isolated but transferred to the oxidation buffer at pH 10.6 by means of gel chromatography on Sephadex G-25. During the chromatography about 50% of the tetrathiol A chain is oxidized specifically to a dithiol A chain disulphide, in which presumably the 6,11-disulphide ring is closen. Generally we observed that the combination yields of modified A or B chains are lower than the yields of combinations of unmodified A or B chains. It seems that there is a correlation between the biological activity of the analogue and the yield obtained by the recombination of the chains.